Due to advantages, such as a high operating voltage, a small volume, a light weight, a high specific capacity, non-memory effect, non-pollution, a small self-discharge and a long cycle life, a lithium-ion secondary battery has been widely applied in various fields, such as communication, electrical appliance, electronic information, power device, storage device and the like, and as the society develops rapidly, people present higher requirements on the lithium-ion secondary battery in energy density, charge-discharge rate, cycle life and safety performance.
Drop test is a relatively strict safety test of the lithium-ion secondary battery. Problems, that top sealing is burst out, electrolyte is leaked, separator wrinkles, internal short circuit is established, tab is broken, and so on, easily occur when the lithium-ion secondary battery is dropped. At present, using an adhesive tape to tie a cell up or enlarging a region for the top sealing may resolve the problems, that top sealing is burst out, electrolyte is leaked and tab is broken and the like, but the above two methods will decrease the energy density of the lithium-ion secondary battery, and cannot resolve the problems that separator shrinks and wrinkles and internal short circuit is established and the like when the lithium-ion secondary battery is dropped. By adhering the conventional double-sided adhesive tape to a position between the cell and a package may resolve the above problems when the lithium-ion secondary battery is dropped, but because the two surfaces of the adhesive tape are both adhesive, when the cell is put into the package, the adhesive tape will be adhered with the package, thereby increasing the difficulty to put the cell into the package (that is the cell enters into the package).